1. Field of the Invention
The present invention relates to the production of commercially valuable aromatic chemicals. More specifically, the field relates to methods and processes for producing aromatic chemicals such as benzene, toluene and the xylenes (BTEX) from wide-boiling temperature range hydrocarbon feedstocks.
2. Description of the Related Art
The efficient and economic production of hydrocarbon based fuels and commodity chemicals is critically important to global markets and commerce. The unrefined, “wide-boiling” temperature range hydrocarbon fractions derived from subterranean reservoirs such as natural gases, light hydrocarbon condensates, natural gas liquids, shale gases and light-gravity crude oils are used to produce light petroleum liquids, typically in the propyl (C3) to dodecyl (C12) hydrocarbon range, via well-known fractionation and distillation processes. In some instances, these processes are comparable to methods using one or more atmospheric, pressure crude separations towers for fractionating traditional crude oil. The fractionated products include liquefied petroleum gas (LPG), natural gasoline, naphtha, and atmospheric gas oil fractions. The resulting products may be commercialized or further processed for the reduction or removal of various impurities found within each boiling fraction to produce refined fuels and hydrocarbon based chemicals such as gasolines, kerosene, diesel fuels, fuel enhancing and stabilizing additives and olefins including ethylene and propylene.
Wide-boiling temperature range hydrocarbons are also useful in the production of light olefins, particularly in the ethyl (C2) to butyl (C4) hydrocarbon range, using steam-cracking reformation or pyrolysis furnace based processes to “crack” the heavy hydrocarbon material into light olefins, commercial polymer subunits and related derivative chemicals.
However, the processing of wide-boiling temperature range hydrocarbon typically results in contamination from sulfurous and nitrogenous compounds as well as heterorganic species. These undesirable contaminants, as well as adventitious metals such as copper, iron, nickel, vanadium and sodium, need to be efficiently removed or reduced from hydrocarbon fractions that ultimately give rise to commercial fuels and commodity chemicals. It is therefore desirable to process wide-boiling temperature range hydrocarbon fractions with minimal treatment for conversion into useful petrochemicals such as aromatic commodity chemicals including benzene, toluene and the xylenes (BTEX). While wide boiling range condensates are considered “alternative” feedstocks that are developed globally from tight-gas formations, BTEX chemicals and their derivatives are less reactive. These valuable chemicals have a global marketplace that is not limited to local use unlike, e.g. light olefins, which are highly reactive and therefore expensive to handle and transport. It is also desirable to reduce or eliminate the necessity for separating wide-boiling temperature range hydrocarbons into fractional components prior to processing and refining as well as reducing the presence of undesirable contaminants such as sulfur, metals and compounds containing the same.